The present invention relates to a shoe with a split sole, particularly useful as a dance shoe, but also useful as an exercise shoe, and particularly relates to sag and stretch resistance of the mid-section of the shoe between its split sole regions.
A typical shoe, dance shoe or dance slipper, or athletic shoe has a sole that extends from the toe to the rear of the heel. For enhancing the flexibility of the shoe to enable the wearer's foot and the shoe to bend and flex more easily, it is known to split the outsole of the shoe between a front portion beneath the toes and the ball of the foot and a rear portion under the heel and to have no sole below the mid-section of the shoe. Instead, the more flexible material of the shoe upper or a similar material provides the connection at the mid-section of the shoe between the sole portions at the rear and the front of the shoe.
Examples of split sole shoes are seen in U.S. Pat. Nos. 4,519,148 and 4,554,749, which suggest a shoe or slipper that is usable in a dance application, and U.S. Pat. Nos. 4,541,186 and 4,542,598, which show an athletic shoe. In shoes of this type, beneath the wearer's foot at the mid-section of the sole, between the sole sections at the front and rear of the shoe, the material of the shoe upper wraps under the foot. The shoe upper also encloses the sides and top of the foot. This design of the upper provides whatever support for the foot the mid-section of the shoe would provide.
The material of which a shoe upper is comprised, typically leather or a fabric in a dance shoe, or another material, are flexible materials which enable the shoe to flex as the foot moves. But, another characteristic of the material of a shoe upper is that it is stretchable, either because it is an inherently stretchable or elastic material, as in some ballet slippers (see U.S. Pat. No. 4,554,749) or it is leather, which inherently stretches when the foot flexes or when laces on the shoe are secured. The flexible material of the shoe upper which is typically used at and under the mid-section of the shoe does not prevent the mid-section, which is not supported by a stiff sole material, from stretching, deforming or sagging, and the arch of the foot is typically not well supported at the mid-section of the shoe.